The use of fenders is well known for many types of vehicle. Fenders are employed to prevent water, mud and debris from being propelled an excessive distance from rotating tyres. Agricultural tractors and other similar utility vehicles have included fenders on front steerable wheels for many years, especially on medium and high horsepower tractors. In such arrangements, each fender typically has an independent support arm which secures the fender to the associated wheel carrier. The support arm is shaped to position the fender above the wheel. Often adjustment means are provided to cater for differently sized wheels and tyres and serve to maintain an acceptable separation between the fender and tyre.
The support arm in known arrangements is fixed to the wheel carrier so that the fender maintains a constant positional relationship with the tyre as the wheel is pivoted during steering. However one drawback faced with the inclusion of fenders is the reduction in available steering angle caused by striking of the fender on the vehicle frame at extreme steering angles. This is compounded by the common design of fenders being wider than the tyre. A simple solution to this problem has been to construct the fenders to be easily removable to allow them to be removed when greater manoeuvrability is required. This solution however is far from satisfactory and, although the cheaper option, is time consuming for the operator.
Another solution has been to mount the support arm to the wheel carrier with a sprung pivoting assembly. The pivoting assembly allows the support arm and fender to pivot with respect to the wheel carrier and tyre thus allowing the wheel to pivot to the maximum steering angle permitted by the geometry of the vehicle frame. The pivoting assembly is provided with a spring which biases the fender and support arm into the neutral position where in the fender is aligned with the tyre.
For shallow steering angles the support arm simply follows the wheel carrier and maintains a fixed relationship between the fender and tyre. At larger steering angles however the fender engages the side of the vehicle frame typically via a stop member and is forced to pivot with respect to the wheel and carrier.
To accommodate the pivoting movement of the support arm, the distance between the arm and the wheel must be sufficient. This places limitations on the placement of suspension components such as hydraulic cylinders connected between the front axle and vehicle frame. Moreover the freedom of the axle to pivot around a longitudinal axis is restricted especially when the track width is narrow.
In known arrangements the axis of pivot is substantially vertical between the support arm and wheel carrier for ease of construction. However, this arrangement also has significant limitations enforced by the limited angle through which the support arm can pivot without striking the tyre. Also, at full steering lock the separation between the support arm and tyre is minimal leading to an increased risk of large debris on the tyre striking the support arm and causing damage.